Electrical connector system

ABSTRACT

An electrical connector system is described for use in subsea environments for providing electrical connection through the wellhead into a tubular element with apertures for carrying electrical cables downhole. The system includes a circumferential electrically conductor ring which is coupled to, and insulated from, a tubular subsea element such as a tubing hanger, by an elastomeric electrically insulating sealing element, surrounding the conductor ring. The conductor ring is coupled to an electrical annular connector and is adapted to receive an electrical connector of a horizontally mounted electrical connector assembly which is hydraulically actuated to penetrate the elastomeric element in the direction transverse to the longitudinal axis of the tubular element to make electrical contact with the conductor ring. This completes an electrical connection from the electrical connector assembly through the conductor ring to the annular connector which, in turn, is coupled to a cable connected to downhole transducers or electrical equipment. The tubular element and conductor ring fit within a wellhead or tubular casing which has an aligned aperture for receiving the horizontally mounted electrical connector assembly.

FIELD OF THE INVENTION

The present invention relates to an electrical connector system for useparticularly, but not exclusively, in the oil industry. The electricalconnector system is particularly suitable for use as a wellheadconnector system used in subsea downhole environments for providingelectrical connection through the wellhead into a tubular element withapertures for carrying electrical cables downhole.

BACKGROUND OF THE INVENTION

Electrical connections are required in subsea equipment so thatelectrical signals can pass to the subsea completion systems allowingsignals to be relayed between downhole transducers and the surface forexample, from permanent monitoring equipment. The signals can also beused to provide information to allow intelligent completion control ofwells. Electrical connections are typically provided in prior artsystems using a vertical stab arrangement. This is an arrangement wheretubular elements typically have a plurality of male electricalconnectors extending from the end of one tubular element for mating withcorresponding female electrical connectors on an adjacent electricalelement. Although such vertical stab elements are commonplace andgenerally work well, they suffer from the significant disadvantage thatcareful orientation is required before the connections are made upotherwise, if an attempt is made to mate two adjacent pieces ofequipment together when the connectors are out of registration, this canresult in damage to the connectors, subsequent retrieval of part, orall, of the connecting equipment being necessary. Orientation is oftentime-consuming and difficult depending on the equipment used and theparticular well conditions. A further disadvantage with the verticalstab arrangement is that it often requires multiple parallel channels tobe made through each tubular element which is expensive and can bedifficult when relatively thin walled elements are required leading to arestriction in the number of cables and consequently monitoringarrangements.

An object of the present invention is to provide an improved electricalconnector system which obviates or mitigates at least one of theaforementioned disadvantages.

This is achieved in the most general sense by providing acircumferentially electrically conductor ring which is coupled to, andinsulated from, a tubular subsea element such as a tubing hanger, partlyby an elastomeric electrically insulating sealing element, surroundingthe conductor ring. The conductor ring is coupled to an electricalannular connector and is adapted to receive an electrical connector of ahorizontally mounted electrical connector assembly which ishydraulically activated to penetrate the elastomeric element in thedirection transverse to the longitudinal axis of the tubular element.

The tubular element, such as a tubing hanger, is machined to receive theconductor ring assembly which includes a conductor ring. The tubularelement and conductor ring fit within a wellhead or tubular casing whichhas an aligned aperture for receiving the horizontally mountedelectrical connector assembly. The electrical connector assembly isactuatable to cause an electrical connector/penetrator to be movedtowards the conductor ring assembly so as to penetrate the elastomericinsulating ring and consequently makes electrical contact with theconductor ring to complete an electrical connection from the electricalconnector assembly through the conductor ring to the annular connectorwhich, in turn, is coupled to a cable connected to downhole transducersor electrical equipment.

Removal of the electrical connector/penetrator results in theelastomeric ring self-sealing to prevent well fluids connecting with theconductor ring and providing an electrical short circuit.

The electrical connector/penetrator is hydraulically operated and isalso spring-biased such that in the absence of any hydraulic pressure tothe connector assembly, the spring is biased to force the electricalpenetrator into contact with the conductor ring to provide an electricalcontact in the event of hydraulic pressure failure.

According to a first aspect of the present invention, there is provideda wellhead electrical connector system for use with a wellhead, saidelectrical connector system having a tubing hanger for location in saidwellhead, said tubing hanger having a circumferential electricalconductor ring assembly disposed at one end thereof, said electricalconductor ring assembly having an electrical conductor ring which iselectrically insulated from the tubing hanger housing, a circumferentialelastomeric sealing ring disposed about the said electrical conductorring for electrically insulating said conductor ring from the tubinghanger and from the external environment, said tubing hanger having atleast one electrical connector disposed in the tubular wall thereof forconveying electrical signals to electrical conductors adapted to becoupled thereto, said elastomeric insulated sealing ring beingpenetrable by an energisable electrical connector coupled to thewellhead to contact said conductor ring and provide an electricalconnection from the energisable electrical connector through the tubinghanger to said at least one electrical connector disposed within saidtubing hanger.

Preferably, the tubing hanger has a machined upper end for receiving theconductor ring assembly, such that when the conductor ring assembly isfitted to the tubing hanger, the external diameter of the tubing hangeris substantially the same as prior to machining the tubing hanger.

Preferably also, the conductor ring assembly has an annular structurewith the conductor ring and elastomeric ring being retained between alower conductor ring housing and an upper retaining ring, theelastomeric element being forced onto the conductor ring via an upperretainer ring acting through a spring onto a spring energiser ring whichabuts the circumferential elastomeric sealing ring. The entire assemblyis retained by an upper annular hanger lock ring which forces theretainer ring and spring and spring energiser ring against theelastomeric element.

Conveniently, the elastomeric ring is shaped to allow expansion whencompressed by the retainer ring so as to provide effective sealingagainst the interior surface of the wellhead and minimise the intrusionof well fluids between the elastomeric sealing ring surface and theopposed surface of the interior of the wellhead.

Conveniently, the springs are wave or disc springs. Preferably, theelastomeric element is a machined or moulded element.

Conveniently, the electrical connector system is electrically coupled toa multi-way connector (i.e. Tronic, U.K.) for conveying electricalsignals from a source external to the connector assembly through theconnector assembly to the conductor ring when in use. Advantageously,the electrical penetrator is coupled to a manual/ROV override boss whichallows the penetrator to be disengaged from the conductor ring in theevent of hydraulic failure.

According to a further aspect of the present invention, there isprovided a method of providing electrical connection through a tubularelement, said method comprising the steps of,

machining a tubular element to provide an annular recessed area,

fitting an electrical conductor ring assembly into the recessed area,

disposing an electrical connector assembly having a moveable electricalconnecting element at a predetermined location external to the tubularelement,

actuating the electrical connecting element in a direction substantiallytransverse to the longitudinal axis of the tubular element to makeelectrical contact with the conductor ring assembly whereby electricalconnection through said conductor assembly such that electrical signalspass from outside the tubular element in a transverse direction via saidconductor ring assembly to electrical connectors within said tubularelement.

Preferably, the method includes the step of biasing the electricalconnector assembly such that in the event of hydraulic failure oractuation of the electrical connector penetrator, resilient means urgethe electrical penetrator into electrical contact with said conductorring.

Preferably, said method includes the step of sealing said conductor ringby said elastomeric ring upon removal of the electrical penetrator.

Preferably, the tubular element is a tubing hanger disposed in awellhead.

According to a further aspect of the invention, there is provided anelectrical conductor ring assembly for use with a downhole tubularelement having an electrical connector in a wall thereof and at leastone annular bore for receiving an electrical conductor, said conductorring assembly being adapted to be coupled to said tubular element, saidconductor ring assembly having a generally circumferential conductorring element, a generally circumferential insulating element forelectrically insulating said conductor ring assembly from the tubularelement, a generally circumferential elastomeric electrically insulatingelement adapted to be disposed radially externally to the conductor ringassembly for effectively sealing the conductor ring assembly fromexternal well fluids, the conductor ring assembly having upper and lowersupport means for urging said elastomeric element into contact with saidconductor ring, said conductor ring assembly being adapted to be coupledto an electrical conductor for fitting into said bore of said tubularelement, said elastomeric sealing ring being resilient such that itdeforms to allow an electrical penetrator to make electrical contactwith said conductor ring, and upon the removal of said electricalpenetrator, the elastomeric sealing element recovers to seal thepreviously penetrated area.

According to a yet further aspect of the present invention there isprovided a non-orientation required electrical connector system for usewith concentric tubular elements coupled together for use within a well,said electrical connector system having a first and a second tubularelement for location in said well, said first tubular element having afirst coupling portion of a first diameter having a generallycircumferentially extending electrical conductor ring assembly disposedat said portion, said electrical conductor ring assembly having anelectrical conductor ring which is electrically insulated from the firsttubular element housing, a generally circumferential elastomeric sealingring disposed about the said electrical conductor ring for electricallyinsulating said conductor ring from the first tubular element and fromthe external environment, said first tubular element having at least oneelectrical connector disposed in a wall of said first tubular elementthereof for conveying electrical signals to electrical conductorsadapted to be coupled thereto, said second tubular element having asecond coupling portion of a second diameter different from said firstdiameter portion and being adapted to be coupled to the first couplingportion of said first tubular element, said second tubular elementhaving an energisable electrical connector coupled thereto, thearrangement being such that when said first and second tubular elementsare coupled together at said first and second coupling portion, saidenergisable electrical connector penetrates said elastomeric insulatedsealing ring to contact said conductor ring and provide an electricalconnection from the energisable electrical connector from the secondtubular element to said at least one electrical conductor within saidfirst tubular element.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will become apparentfrom the following description when taken in combination with theaccompanying drawings in which:

FIG. 1 is a diagrammatic cross-sectional view through a wellhead with atubing hanger mounted therein and a connector assembly mounted at theside of the wellhead in accordance with an embodiment of the presentinvention;

FIG. 2 is an end view of FIG. 1 taken on the lines 2—2, and

FIG. 3 is a cross-sectional view of the complete tubing hanger shown inFIG. 1, but to a reduced scale, with the conductor ring assembly and theelectrical connector assembly shown in broken outline only.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is first made to FIG. 1 of the drawings which depicts the toppart of a wellhead, generally indicated by reference numeral 20, intowhich is located a tubing hanger 22, in a conventional manner. The topof the tubing hanger 22 has been machined to define an annular recess 24into which is disposed a conductor ring assembly, generally indicated byreference numeral 26, which has a circumferential conductor ring 28 forbeing electrically connected to an electrically conductive penetrator 30of an electrical connector assembly, generally indicated by referencenumeral 32, which is mounted on the side of the wellhead 20 as shown.When the electrical connector assembly is actuated, a spring-biasedelectrical connector/penetrator 34 is urged through an aperture 36 inthe wellhead to penetrate the conductor ring assembly 26 and mate withthe conductor ring 28 for providing electrical contact, as will be laterdescribed in detail.

It will be seen from FIG. 1 that the tubing hanger 22 has an upper bore38 for receiving an electrical connector 39 which is coupled between thecircumferential conductor ring 28 of the conductor ring assembly 26 andan electrical cable 40 as shown in broken outline. The bore 38 narrowsinto a longitudinal bore 42 which extends throughout the length of thetubing hanger 22 as best seen in FIG. 3 of the drawings. The cable 40passes through bore 42 for subsequent connection to a further cable ortransducers downstream of the tubing hanger 22.

The conductor ring assembly 26 is dimensioned and proportioned to fitinto the annular recess 24 and the tubing hanger 22 as shown in FIG. 1of the drawings, such that the tubing hanger, when fitted with theconductor ring, fits readily within the wellhead 20 as shown in FIG. 1.

The conductor ring assembly 26 has a circumferential copper conductingring 28 which is electrically insulated from conductive ring housing 44by an electrical insulator 46 at its radially inward position and alsobeneath the conductor ring 28.

A machined elastomeric ring 48 is disposed around the conductor ring 28above and radially outwardly of conductor ring 28 as shown in FIG. 1 ofthe drawings. The elastomeric ring 48 is effectively sandwiched betweenthe conductor ring housing 44 and an upper energiser ring 52 and aretainer ring 54 which screws into housing 44. A wave spring 56 isdisposed between the retainer ring 54 and the energiser ring 52 forurging the energiser ring 52 against the elastomeric element 48. Ahanger lock ring 58 locks the retainer ring 54 in place to preventinadvertent unscrewing of the assembly during tool makeup.

When the retainer ring 54 is screwed into the conductor housing 44 iturges the energiser ring 52 against the elastomeric seal 48 therebydeforming the elastomeric seal so that it forces face 48 a slightlyproud of the surface of the tubing hanger so that there is a tight fitagainst the interior surface 20 a of the wellhead to provide aneffective seal against well fluids, but not tight enough to prevententry of the tubing hanger into the wellhead or damage to elastomericseal.

Reference is now made to the electrical connector assembly, generallyindicated by reference numeral 32. It will be seen that this consists ofa housing 60 which is generally cylindrical, as best seen in FIG. 2. Thehousing has a front circular plate 62 with a plurality of apertures 64which are aligned with corresponding apertures 66 in the wellhead toallow the assembly 32 to be bolted to the wellhead by bolts (not shown).

Disposed within the assembly 32 is a bore 68 into which is disposed aplunger 70. The plunger 70 has at one end an electricalpenetrator/connector, generally indicated by reference numeral 72, whichhas a leading conductor end 72 a which is shown in electrical contactwith conductor 28 in FIG. 1. The plunger 70 is reciprocally moveablewithin the bore 70 a and is urged into the electrically connectingposition shown by coil spring 74 so that the leading end 72 penetratesthe elastomeric seal 48 as shown and makes electrical contact with theconductor ring 28. A hydraulic port 76 is disposed in the housing of theassembly 32 for receiving a hydraulic line (not shown in the interestsof clarity). When pressure is applied to the hydraulic line, the plunger70 is moved to the right, against the force of coil spring 74, so thatthe penetrator 72 is retracted from its engagement with the conductorring assembly. When this occurs the resilience of the elastomeric ring48 seals the hole made by the leading end of the penetrator 72 a toprevent ingress of well fluid making contact with the conductor ring 28.The electrical connector 72 is connected via a cable (not shown) in bore77 to typically a Tronic (Ulverston, U.K.) four way connector 78, whichcan, in turn, receive a mating coupling, not shown, to convey electricalsignals to and from the penetrator 72.

A manually operable plunger retraction assembly, generally indicated byreference numeral 80, is disposed at the outermost end of the assembly32. This can be actuated manually or by a ROV to retract the penetrator72 and plunger 70 into the assembly 32 in the event of failure ofhydraulic pressure. In the event hydraulic pressure does fail, theelectrical connector assembly is designed as a “fail-connect” system,whereby the coil spring 74 urges the plunger and connector/penetrator 72a into electrical contact with the conductor ring so that there iselectrical continuity throughout the system. In the position shown inFIG. 1 electrical connection is thereby possible via the four wayconnector 78 through the penetrator 72, the leading end of thepenetrator 72 a to the conductor ring 28 and the electrical connector 39and cable 40.

It will be appreciated that in this arrangement the connector assemblycan be disposed at any position around the wellhead at a suitable levelso that when the connector/penetrator 72 a is actuated to penetrate theelastomeric ring 48 it makes electrical contact with the conductor ring28. Therefore, this effectively allows 360° connection around thewellhead and thus the connection is independent of tubing hangerorientation. In addition, because the penetrator assembly is mounted asshown connection is made horizontally through the wellhead to mate withthe conductor ring 28 instead of a vertical stab connection as in theprior art. This means that less machining of the tubing hanger andtubular connections is required to create longitudinal bores, such asbore 38 and 42, minimising cost and minimising possible damage to thecomponents in the event of misalignment. In this case, misalignment isminimised because the electrical connector assembly can only be fittedat one location and the tubing hanger can only be disposed in thewellhead at one level so that when the electrical connector assembly isactuated, penetration occurs at the correct level so that electricalconnection is made between the penetrator and the conductor ring.

Reference is now made to FIG. 3 of the drawings which depicts the entiretubing hanger 20 (DrillQuip) from which it will be seen that the bore 42extends the length of the tubing hanger. The wellhead 20, the conductorassembly 26 and the electrical connector assembly are shown in brokenoutline. It will be seen that the tubing hanger has a circumferentiallocating ring 22 a for locating the tubing hanger in the wellhead at thecorrect location to allow registration of the electrical connectorassembly 32 and the conductor ring assembly 28 as described above.

Various modifications may be made to the embodiment hereinbeforedescribed without departing from the scope of the invention. Theinvention may be applied to providing electrical connection betweentubular elements within a well where non-orientation is required betweenrespective adjacent tubular elements which are screwed or otherwisecoupled together. The tubular elements are of different diameters tofacilitate transverse of horizontal penetration by the penetratorthrough the elastomeric ring. The ring is conveniently on the lowertubular element and at that level is of a smaller diameter than thediameter of the element at the level of the penetrator so that the toptubular element fits over the lower element before penetration occurs.In an alternative arrangement the lower element may be of a largerdiameter and the top tubular element smaller at the penetrator/ringlevel so that it fits inside the lower element. The conductor ringassembly may be disposed in any suitable tubular element as long asthere is registration between the location of the tubular element andthe location of the electrical connector assembly so that when both aredisposed in oil well apparatus and actuation of the plunger 70 occursthere is registration between the penetrator 72 and the conductor ring28. The plunger 70 may be pneumatically or electrically controlledinstead of hydraulically controlled. The conductor ring may be made ofany suitable conducting material, other than copper, for example steel,or a conductive polymer. The elastomer 48 may be replaced by anysuitable elastomeric material which provides electrical insulation andis sufficiently resilient to seal holes made by a penetrator upon theretraction. The wave springs may be replaced by disc springs.

It will be appreciated that the principal advantage of the presentinvention is that it provides for electrical connection through atubular element which does not depend on the orientation of a stack oftubular elements, thus facilitating rapid and effective assembly ofsubsea components avoiding the requirement of orientation. Therefore,the provision of an orientation-free system minimise cost. In addition,the use of a horizontal electrical connection avoids the need forcomplex machining of bores in tubular elements and is a particularadvantage where tubular elements are relatively thin walled, thusminimising machine costs and allowing for electrical connection to bemade in such think walled tubular elements which hitherto have not beenable to receive electrical connection. The invention has particularapplication in subsea assemblies for permanent monitoring andintelligent well completion.

What is claimed is:
 1. A wellhead electrical connector system for usewith a wellhead, said electrical connector system having a tubularelement for location in said wellhead, said tubular element having agenerally circumferentially extending electrical conductor ring assemblydisposed at one end thereof, said electrical conductor ring assemblyhaving an electrical conductor ring which is electrically insulated fromthe tubular element, a generally circumferential elastomeric sealingring disposed about the electrical conductor ring for electricallyinsulating said conductor ring from the tubular element and from theexternal environment, said tubular element having at least oneelectrical connector disposed in a wall of said tubular element thereoffor conveying electrical signals to electrical conductors adapted to becoupled thereto, said elastomeric sealing ring being penetrable by anenergisable electrical connector coupled to the wellhead to contact saidconductor ring and provide an electrical connection from the energisableelectrical connector through the tubular element to said at least oneelectrical connector disposed within said tubular element.
 2. A wellheadelectrical connector system as claimed in claim 1 wherein theelastomeric ring is shaped to allow expansion when compressed by theretainer ring so as to provide effective sealing against an interiorsurface of the wellhead and minimise the intrusion of well fluidsbetween an elastomeric sealing ring surface and an opposed surface ofthe interior of the wellhead.
 3. A wellhead electrical connector systemas claimed in claim 1 wherein the elastomeric ring is a machinedelement.
 4. A wellhead electrical connector system as claimed in claim 1wherein the electrical connector system is electrically coupled to amulti-way connector for conveying electrical signals from a sourceexternal to the connector assembly through the connector assembly to theconductor ring when in use.
 5. A wellhead electrical connector system asclaimed in claim 1 wherein the energizable electrical connector iscoupled to a manual/ROV override boss which allows the connector to bedisengaged from the conductor ring in the event of hydraulic failure. 6.A wellhead electrical connector system as claimed in claim 1 wherein theelastomeric ring is a molded element.
 7. A wellhead electrical connectorsystem as claimed in claim 1 wherein the tubular element is a tubinghanger.
 8. A wellhead electrical connector system as claimed in claim 7wherein the tubing hanger further comprises a machined upper end forreceiving the conductor ring assembly, such that when the conductor ringassembly is fitted to the tubing hanger, an external diameter of thetubing hanger is substantially the same as prior to machining the tubinghanger.
 9. A wellhead electrical connector system as claimed in claim 7wherein the conductor ring assembly further comprises an annularstructure with the conductor ring and elastomeric ring being retainedbetween a lower conductor ring housing and an upper retaining ring, theelastomeric ring being forced onto the conductor ring via the upperretainer ring acting through a spring onto a spring energiser ring whichabuts the circumferential elastomeric sealing ring.
 10. A wellheadelectrical connector system as claimed in claim 9 wherein the entireassembly is retained by an upper annular hanger lock ring which forcesthe retainer ring and spring and spring energiser ring against theelastomeric ring.
 11. A wellhead electrical connector system as claimedin claim 9 wherein the spring is a wave spring.
 12. A wellheadelectrical connector system as claimed in claim 9 wherein the spring isa disc spring.
 13. An electrical conductor ring assembly for use with adownhole tubular element having an electrical connector in a wallthereof and at least one annular bore for receiving an electricalconductor, said conductor ring assembly being adapted to be coupled tosaid tubular element, said conductor ring assembly having a generallycircumferential conductor ring element, a generally circumferentialinsulating element for electrically insulating said conductor ringassembly from the tubular element, a generally circumferentialelastomeric electrically insulating element adapted to be disposedradially externally to the conductor ring assembly for effectivelysealing the conductor ring assembly from external well fluids, theconductor ring assembly having upper and lower support means for urgingsaid elastomeric element into contact with said conductor ring, saidconductor ring assembly being adapted to be coupled to an electricalconductor for fitting into said bore of said tubular element, saidelastomeric element being resilient such that it deforms to allow anelectrical penetrator to make electrical contact with said conductorring, and upon the removal of said electrical penetrator, theelastomeric element recovers to seal the previously penetrated area. 14.A non-orientation required electrical connector system for use withconcentric tubular elements coupled together for use within a well, saidelectrical connector system having a first and a second tubular elementfor location in said well, said first tubular element having a firstcoupling portion of a first diameter having a generallycircumferentially extending electrical conductor ring assembly disposedat said portion, said electrical conductor ring assembly having anelectrical conductor ring which is electrically insulated from the firsttubular element housing, a generally circumferential elastomeric sealingring disposed about the said electrical conductor ring for electricallyinsulating said conductor ring from the first tubular element and fromthe external environment, said first tubular element having at least oneelectrical connector disposed in a wall of said first tubular elementthereof for conveying electrical signals to electrical conductorsadapted to be coupled thereto, said second tubular element having asecond coupling portion of a second diameter different from the diameterof said first coupling portion and being adapted to be coupled to thefirst coupling portion of said first tubular element, said secondtubular element having an energisable electrical connector coupledthereto, the arrangement being such that when said first and secondtubular elements are coupled together at said first and second couplingportions, said energisable electrical connector penetrates saidelastomeric sealing ring to contact said conductor ring and provide anelectrical connection from the energisable electrical connector from thesecond tubular element to said at least one electrical conductor withinsaid first tubular element.
 15. A connector system as claimed in claim14 wherein the first coupling portion of the first tubular element is ofa smaller diameter than the second coupling portion of the secondtubular element.
 16. A connector system as claimed in claim 14 whereinthe first coupling portion of the first tubular element is of a largerdiameter than the second coupling portion of the second tubular element.